A continuing demand exists for a simple, highly efficient and inexpensive thermal power plant which can reliably provide low cost electrical and mechanical power. This is because many electrical and/or mechanical power plants could substantially benefit from a prime mover that offered a significant improvement over currently practiced cycle efficiencies in power generation. This is particularly true in medium size power plants--largely in the 10 to 100 megawatt range--which are used in many industrial applications, including stationary electric power generating units, rail locomotives, marine power systems, and aircraft engines.
Medium sized power plants are also well suited for use in industrial and utility cogeneration facilities. Such facilities are increasingly employed to service thermal power needs while simultaneously generating electrical power at somewhat reduced overall costs. Power plant designs which are now commonly utilized in co-generation applications include (a) gas turbines, driven by the combustion of natural gas, fuel oil, or other fuels, which capture the thermal and kinetic energy from the combustion gases, (b) steam turbines, driven by the steam which is generated in boilers from the combustion of coal, fuel oil, natural gas, solid waste, or other fuels, and (c) large scale reciprocating engines, usually diesel cycle and typically fired with fuel oils.
Of the currently available power plant technologies, diesel fueled reciprocating and advanced aeroderivative turbine engines have the highest efficiency levels. Unfortunately, with respect to the reciprocating engines, at power output levels greater than approximately 1 megawatt, the size of the individual engine components required become almost unmanageably large, and as a result, widespread commercial use of single unit reciprocating engine systems in larger sizes has not been developed. Gas turbines perform more reliably than reciprocating engines, and are therefore frequently employed in plants which have higher power output levels. However, because gas turbines are only moderately efficient in converting fuel to electrical energy, gas turbine powered plants are most effectively employed in co-generation systems where both electrical and thermal energy can be utilized. In that way, the moderate efficiency of a gas turbine can in part be counterbalanced by using the thermal energy to increase the overall cycle efficiency.
Fossil fueled steam turbine electrical power generation systems are also of fairly low efficiency, often in the range of 30% to 40% on an overall net power output to raw fuel value basis. Still, such systems are commonly employed in both utility and industrial applications for base load electrical power generation. This is primarily due to the high reliability of such systems.
In any event, particularly in view of reduced governmental regulation in the sale of electrical power, it can be appreciated that it would be desirable to attain significant cost reduction in electrical power generation. Fundamentally, particularly in view of long term fuel costs, this would be most effectively accomplished by generating electrical power at a higher overall cycle efficiency than is currently known or practiced.